10 years of use with 6 hard driving on a 300B sounds like a very good reason to change. The Tung Sol 6SL7 is fine but you can do a lot better than Westinghouse on the 6SN7. Some Sylvanias perhaps there are quite a few good ones still floating around. The CV=1988 by Brimar is superb. The luxury of a new finely made 300B is wonderful news to my ears even though I don't have an amp to use them in. The Psvanes are getting mixed reviews I would proceed with caution. Otherwise I would add some heavy custom brass footers from Edensound and good platforms and call it a day. Like the others said enjoy what you have got.
Where should I go next? Where are my weak links?
I am now running a much simpler system than I did in the past. I have a pair of Zu Audio Essence speakers coupled with a Mini-Method sub. They are driven by a pair of Manley Neo-Retro 300b amplifiers. I listen mostly to vinyl. My turntable is a slightly upgraded VPI Scout with the SDS drive, scoutmaster platter, ring clamp and VPI mini feet. The scout is loaded with a Benz Micro L2 wood cartridge. I use a Linn Linto phono stage and a Manley Shrimp preamplifier. I condition the power on my source components with a Furman Elite 15. All my interconnect cables are Zu Audio Missions and my power cords are Zu Boks. My speaker cables are Zu Libtecs. I really love the sound produced by my system. I did not really understand how dynamic my 300b amps could sound until I coupled them with a copacetic set of speakers. But, being as I am, I can't help looking to improve on what I have. I am aware that I am not the most knowledgeable or experienced audiophile, so I am hoping for some useful suggestions from all you savvy folk out there. I am not looking to revolutionize my system at this time, just to refine what I have. I wonder whether an improved phono stage might be in the cards.